US2249325A - Apparatus for forming tubular elements - Google Patents

Description

July 15, 1941. A. A. PRUCKNER APPARATUS FOR FORMING TUBULAR ELEMENTS (riginal Filed Aug. 15, 1938 4 SheetsSheet l INVENTOR.

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July 15, 1941. A. A. PRUCKNER APPARATUS FOR FORMING TUBULAR ELEMENTS Ofiginal Filed Aug. 15, 1938 4 Sheets-Sheet 2 INVENTOR.

Anion A .Prac'lm er.

A TTORNE Y.

y 1941- A. A. PRUCKNER 2,249,325

APPARATUS FOR FORMING TUBULAR ELEMENTS Original Filed Aug. 15, 1938 4 Sheets-Sheet 5 FiiQTJO.

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APPARATUS FOR FORMING TUBULAR ELEMENTS Original Filed Aug. 15, 1938 4 Sheets-Sheet 4' 7 nvvmv'ron.

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Patented July 15, 1941 APPARATUS FOR FORMING TUBULAR ELEMENTS Anton A. Pruckner, Norristown, Pa, asslgnor to Superior Tube Company, Philadelphia, Pa., a corporation of Pennsylvania Original application August 15, 1938, Serial No.

Divided and this application September 26, 1939, Serial No. 296,576

8 Claims.

My invention relates to apparatus for forming tubular elements, including more particularly me- .tallic tubular elements of small diameter and suited for various purposes, including especially for use as electrodes or other components of thermionic tubes.

In accordance with my invention, a length of tubing is intermittently fed longitudinally through a rotatable chuck which clamps it, between the successive feeding operations, to effect its rotation while in engagement with a scoring disk moved away from the path of the tubing before the beginning of each feeding movement thereof; the extent of feed is determined by a stop movable into and out of the path of the tubing by mechanism operating in timed relation to mechanism controlling clamping and release of the tubing by the chuck; the scored end sections of the tubing are, in turn, detached from the remainder of the tubing by a striking element operating in timed relation to the chuck control mechanism.

Further in accordance with my invention, the tube is supported adjacent the scoring disk by auxiliary chuck jaws whose movement toward and from the tubing is controlled by mechanism operating in timed relation to movement of the scoring disk toward and from the tubing and to operation of the striking element.

Preferably, the arrangement for feeding the tubing comprises a pair of concentric sleeves which, upon relative motion in one direction, compress a split sleeve firmly to hold the tubing for movement therewith and which, upon their relative motion in opposite direction, permit the split sleeve to expand and release the tubing.

My invention further resides in the features of construction, combination, and arrangement hereinafter described.

This application is a division of my application Serial No. 224,928, filed August 15, 1938.

For an understanding of my invention, reference is to be had to the accompanying drawings,

in which:

Fig. 1 is a side elevational view, with some parts broken away and some in section, of a. machin for making tubular elements;

Fig. 2, with some" parts in section, is a plan view of the machine shown in Fig. 1;

Fig. 3 is a detail view, in plan and on enlarged scale, of tube-feeding and tube-holding mechanism shown in Figs. 1 and 2;

Fig. 4 is a side elevational view of chuck mechanism shown in Fig. 3 with some parts broken away;

Fig. 5 is a front elevational view, partly in section of the chuck mechanism shown in Fig. 4;

Fig. 6 is a detail view in front elevation, of a collet-chuck shown in Fig. 3;

Fig. 7 is a detail view, partly in section and on enlarged scale, of parts of the feeding mechanism shown in Fig. 3;

Fig. 8 is aside elevational view on enlarged scale of control mechanism for the parts shown in Fig. 7;

Fig. 9 is a front elevational view, on enlarged scale, taken on line 9-9 of Fig. 2;

Fig. 10 is a front elevational view, on enlarged scale, taken on line Ill-Ill of Fig. 2;

Fig. 11 is a, front elevational view, on enlarged scale, taken on line ll-ll of Fig. 1;

Fig. 12 is a front elevational view, on enlarged scale, taken on line l2|2 of Fig.2;

Figs. 13 to 18 illustrate the successive steps of a method for making beaded tubular elements;

Fig. 19 is a side elevational view, on enlarged scale, of heading mechanism shown in Figs. 1 and 2;

Fig. 20 is a front elevational view of the mechanism shown in Fig. 19.

Referring to Figs. 1, 2' and 3 of the drawings, the motor I is connected by pulley 2, belt 3 and pulley 4 to the hollow spindle 5 upported by the 1 bearing members 6 extendingabove the frame the spindle.

or bed 1. At the forward end of spindle 5 the bore thereof tapers outwardly to fit the corresponding taper of the head 8 of the collet-chuck 9 whose shank l0 closely fits the main bore of The inner end of the shank III, of reduced diameter, is threaded to receive one end of the sleeve l l which extends through the spindle and projects to substantial extent beyond the rear end thereof.

To the rear extension of the sleeve II is serear bearing 6 to serve as a thrust member preeluding axial movement of the spindle 5 to the right. Axial movement of the spindle 5 to the I left is prevented by engagement between the forward face of the front bearing 6 and the rear face of the member l5 secured to the forward extension of spindle 5.

The nuts l6, l1, threaded upon the rear extension of the sleeve ll, hold between them the inner race l9 of a ball bearing whose outer race 20 is pivotally held (Fig. 9) to the arm 22 pivotally mounted upon the upper end of a bracket 23, Fig. 1, extending upwardly from theirame I of the machine. Near the other end of the arm 22 is mounted the cam follower 24 held against the cam 25 by spring 26 connected between extension 21 of arm 22 and the stationary bracket 28. The cam 25 is secured to shaft 29 driven from motor I at speed substantially lower than the speed of spindle through the belt 30, pulley 3| on shaft 32 of a reduction gear box 33 (Fig. 1), the shaft 34, sprocket 35, chain 36 and sprocket 31 on shaft 29.

The speed of shaft 29, which makes one revolution for each cycle of themachine, may be from 50 to 80 revolutions per minute or higher; the speed of the spindle 5 is substantially higher, and preferably of the order of 1800 revolutions per minute. The most suitable spindle speed will depend upon the diameter and material of tubing T. When, during each revolution of cam 25, the cam follower 24 moves to the right (Figs. 1 and 3) the rotating sleeve II is moved to the right, permitting the split head 9 of the collet-chuck 9 to v expand and so release its grip upon the piece of metallic tubing T which extends entirely through the spindle 5 and through other elements of the machine, as hereinafter described. When cam forces the arm 22 to the left, the sleeve I I is likewise moved to the left to draw in the colletchuck, the taper at the forward end of the bore of spindle 5 compressing the split head 8 again firmly to hold the tubing T.

During the interval in each cycle of the machine, when the collet-chuck is released from the tubing T, the tubing is fed to the right to a predetermined extent through the spindle by the mechanism now described. Within the sleeve I I are two more concentric sleeves 38, 39 (Fig. 3). The outer of these two sleeves is provided with a guide extension 38a of reduced diameter which is slidably received by the bore of the shank II] of the collet-chuck 9.

Upon the other end of the sleeve 38 are threaded the nuts 40', 4| which hold between them the inner race 42 of a ball bearing whose outer race 43' is pivotally mounted by pins 44, 44 to arm 45 whose upper end (Figs. 1 and 8) is pivotally mounted upon the member 46 attached to member 12 on the forward end of the linearly reciprocable tubular member 41. The lower end of arm 45 is provided with a cam follower 48 received by the groove of cam 49 attached to shaft 50 supported for rotation and axial reciprocation by the bearing members 5| and 52 extending upwardly from the frame 1 of the machine (Fig. 1).

When cam 49 swings the member 45 in clockwise direction (Fig. 8), the sleeve 38 is moved to the left so that the taper 53 at the forward 39. This relative movement of the sleeves 38, 39

compresses the split sleeve 54 firmly to hold the tubing T which extends therethrough. While the sleeves 38, 39 are in this position, both sleeves are moved to the right to feed the tubing T through the collet-chuck which, at this time, is open or released from the tubing. To effect this feeding movement, there are secured to the rear extension of the innermost sleeve 39 the stops 56 and 51 (Figs. 1, 2 and 3); the forward stop 56, as more clearly shown in Fig. 3, abuts the forward end of a ball bearing 58 at the forward end of the tubular member 41, and the rear stop 61 engages the rear face of a ball bearing 59 disposed within the other end of the tubular member 41. There is connected to the member 41, intermediate its ends, the support 66 for the pin 6| (Fig. 2) connected by link 62 to the upper end of the lever 63 pivotally mounted at 64 (Fig. 1) upon the frame 1 and whose lower arm is connected by link 65 to the lower arm of a similar lever 66 pivoted at 61 upon the frame 1 and whose upper arm carries a cam follower 68 received by the groove in cam 69 on the shaft 29.

During each revolution of shaft 29, the cam 69 effects a forward and a return stroke of the tubular member 41 to reciprocate the inner sleeve 39. The cam 49 is so timed that just before beginning of the forward movement of sleeve 39, the sleeve 39 is moved to the left with respect thereto to close the split sleeve 54 upon the tubing T so that, during forward movement of member 41 and sleeves 39 and '39 under the control of cam 69, the tubing T is moved therewith bodily to the right through chuck 9 which at this time is open. After the collet-chuck 9 has closed upon the tubing T under the control of its cam 25, the cam 49 effects movement of sleeve 39 to the left with respect to sleeve 39 to release the split sleeve 54 so that, during the return stroke of sleeves 33 and 39 to the left, the split sleeve I with respect to member 41. The shaft 50 of cam- 49 is driven from the shaft 29 by the sprocket 13, chain 14 and sprocket 15 slidably keyed to the axially reciprocable shaft 50. The extent of feed of the tubing T may conveniently be varied by shifting the points of connection of link 65 to the levers 63 and 66 interposed between the cam 69 and the slidable member 41; to that end, the lower arms of the levers 63, 66 may each be provided with a series of pivot-pin holes.

Preferably, the stroke of member 41 is selected to be slightly greater than the desired length of the tubular electrodes or like tubular elements to be cut in succession from the forward end of the tubing T projecting beyond the collet-chuck; an exactly correct length of tubing beyond the chuck is determined by a stop 16 controlled as hereinafter described. The frictional grip of the split sleeve 54 upon the tubing T is sufficient to effect its forward feed, and yet is not so great as to in any way damage the tubing when its forward end is arrested by the stop and the sleeve 54 is forced to continue its feeding movement for a slightly longer time by continued forward movement of the inner sleeve 38. This continued grip and feed forward holds and forces tubing against the stop-thus insuring exact length of the projecting section of the tubing. The stop 16, as more clearly appears in Figs. 1, 2 and 12, comprises an arm whose forward end is adapted to swing into the axis of rotation of member 5 to intercept the tubing being fed axially thereof, as hereinafter described. The rear end of the arm 16 is pivotally mounted upon a bracket 11 secured to a slide 18 adjustable, as by the threaded member 19, in direction parallel to the axis of rotation of member 5. Upon the arm 16 is mounted the cam follower 88 for engaging the periphery of the cam 8I on the shaft 28 which makes one revolution for each cycle of themachine. Preferably, the arm 16 is biased to maintain engagement of cam follower 88 with cam M by the spring 18a. The cam 8I is so shaped that suitably before the end of the forward stroke of the tubular feed member 81, the arm 18 is dropped (Fig. 13) to intercept the leading end of the tubing T being fed through the collet-chuck. Thereafter, the cam 8I lifts the arm 18 and holds it above the tubing (Figs. 12 and 14) during other operations, hereinafter described, performed upon the projecting piece of tubing.

Beyond the forward end of the spindle there is adjustably mounted, upon the bed 1 of the machine, the supporting member 82 for the bar 83 which carries .the grooved tool 88 (Figs. 1, 2. 19 and 20). To the bar 83 is secured the arm 85 which carriesthe cam follower 85 engaged by'cam 81 on the one-time shaft 28. After the stop 18 is lifted, the cam 81 permits movement of bar 83 to the left (Figs. 2 and 14) so that the forward end. of the rotating tubing held by the chuck 8 is received by the groove in tool 88, and as the movement of tool 88 continues to the left under the control of spring 83a and cam 81, the projecting portion of the tubing is bent upwardly, Fig. 15, due to the upward slope of the bottom of the groove in tool 88. The sides of the groove prevent rotation: of the projecting section of the end of spindle 5. The outer ends of the slides 83 are tapered to match the inner taper of ring 88 which encircles member I5. Springs 85 bias the pair of slides and-supporting members 82 away from each other. The ring 88 is attached to member 81 whose hub 88 supports the inner race 88 of a ball-bearing whose outer race I88 receives pivot pins I8I at the forked end of lever I82 pivoted at I83 to the standard I88 extending upwardly from frame 1 ofthe machine. Clockwise movement of lever I82 (Figs. 1 and 8) effects movement of ring 88 to the left so that the aforesaid inner taper thereof forces slides 83, 83

- and jaws 82'toward and into engagement with position.

tube about the axis of rotation of the chuck and,

in fact, prevent all rotation of the bent section except about its own axis. In consequence, there is formed, as shown in Fig. 15, a peripheral bead B at the bend in the tubing. (Bead BI was similarly formed in the prior cycle of the machine.)

To afford fine adjustment of the height of the bead, the angle between the axis of rotation of the tubing and the line of reciprocation of the member 88 may be varied; for example, as shown more clearly in Fig. 19, the supporting frame 82 for bar 83 may be pivotaily mounted upon the base member 88 and the angle controlled by the threaded stop 88 whose lower end abuts the upper face of member 88. A spring 88 between member 82 and 88 may be used to prevent vibration of the machine from disturbing the desired angular relation; spring 88, compressed between the extension of member 82 through which stop 88 is threaded and the upper cross-piece of member 88, supplements gravity in maintaining engagement of stop 88 with the upper face of the lower part of member 88.

The two sections of tubing T, one section being the straight section held by the chuck 8 and the other section being the bent section projecting 'beyond the chuck, continuously rotate, each about its own axis, and centrifugal force causes the forward end of the bentsection to follow the bottom of the-groove as the member 88 retracts so that the two sections of tubing again come into alignment when tool 88 is fully retracted (Fig. 16). This self-straightening of the tubing is not effected if rotation of the tubing is stopped during the retraction of member 88.

After the tubing has been straightened, the pair of members 82 having complementary semi-circular notches move into engagement with the tubing beyond bead B to embrace and support it during a cutting-off operation hereinafter described. The jaw members 82, 82, as more clearly appears in Figs. 3, 4 and 5, are mounted upon slides 83, 83 received by radial grooves in the front face of member I5 attached to the forward The movement of lever I82 is controlled by cam I on the one-time shaft 28; the face of the cam engages the cam follower I85 on arm I81 pivoted at I88 to standard I88 and connected by link I88 to lever I82.

Jaws 82 are replaceable by similar jaws differently notched to accommodate different sizes of tubing and having bases 82a of different length to support the tubing at different desired distances beyond the collet-head 8.

The cam I85 is so shaped that the laws 82 close upon the tubing after it has been beaded and straightened and before engagement therewith of the scoring disk II8 (Figs. 1, 2, 10 and 1'7) rotatably mounted upon member III pivotally mounted at II2 upon the adjustable slide H3. The post II 8 extending upwardly from slide II3 provides a pivotal support II5 for lever "8 which at its forward end threadably receives the adjusting screw II1 having at its lower end a flared or head member for supporting member III.

Upon the supporting member II8 for slide H3 is pivotally mounted at II8 the lever I28 having at its lower end a cam follower I 2I maintained in engagement with cam I22 on shaft 28 by spring I23. From the upper end of lever I28 extends a pin for supporting the roller I28 which continuously engages the upper face of lever H6. When cam I22 permits spring I23 to swing arm I28 in clockwise direction,.arm H6 is actuated in clockwise direction to liftv the scoring disk or cutter II8. When cam I22 swings arm I28 in reverse direction, the biasing spring IIIia moves arm H6 in clockwise direction so to effeet engagement of rotatable scoring disk II8 with the rotating tubing T (Fig. 17). The groove Illa in member III is to provide a clearance for the bead BI. The rotation of tubing T while disk II8 rests upon it and is rotated thereby produces a circumferential score or groove which weakens the wall of the tubing. The scoring action can be nicely regulated by adjustment of screw II 1 which controls the angular relation between member III and arm IIS and by adjustment of screw I25 which varies the position of slide II3 to change the distance between pivot II2 of member I and the axis of rotation of the tubmg.

Though rotatable disk III) is preferred, it may be replaced by a straight-edged knife non-rotatably attached to member H8.

The distance from the chuck 8 at which the cutter disk II8 engages tubing T may be varied by adjusting the screw I26 which threadably en.- gages the support H8 and passes through the stationary bracket I21. the support H8 is moved along the tracks I28 By' turning screw I28,

parallel to'the axis of rotation of tubing T. Support H8 may be clamped in the desired position by tightening bolts I23 which pass through slots in the base of support 3 into the frame member I. Similarly, the slidable support 11 for the stop arm 16 may be held in desired position by bolts I30 which pass through slots in the base of support 11 into frame member I.

After the tubing has been scored, and preferably after knife III has been lifted therefrom, it is struck beyond the scoring by tool l3l (Fig. 18) to break or sever the tubing at the scoring and so detach therefrom the beaded element ET suited for use as the cathode, or other component of an electronic tube, such as a spacing sleeve, or for any other purpose requiring a tubular beaded element. The described method of detaching the beaded elements from the remaining length of tubing'provides for clean-cut, burr-free ends thereof.

As more clearly appears in Fig. 11, the striking tool l3! extends from arm I32 pivotally mounted upon bracket I33 secured to the frame of the machine. The spring I34 biases the arms to maintain engagement between cam follower I35 at the upper end thereof and cam I36 on the one-time shaft 29.

After an element ET has been detached from the tubing, the striker l3| is returned to its original position, supporting jaws 92 move away from each other to clear bead B, stop 16 is dropped to the position shown in Fig. 13, the tubing '1 is released by opening of chuck Sand the feeding of the tube T is initiated to bring the next section of tubing in position beyond the chuck (Fig. 13) for formation of another element ET by the steps previously described and diagrammatically shown in Figs. 13 to 18.

With the preferred machine disclosed, all of the operations are performed automatically and the cycles follow without pause or interruption to form tubular elements until a length of tubing is exhausted. The operator then threads the leading end of another elongated piece of tubing through the machine and restarts it.

At considerable sacrifice in the rate of production, any or all of the movements effected by the cams on the one-time shaft 29 can be effected manually and any or all of the steps of the method shown in Figs. 13 to 18 may be effected either manually or by mechanism differing substantially from the mechanism shown in Figs. 1 and 2.

With the full-automatic machine of Figs. 1 and 2, beaded cathodes having a diameter of from about 0.010" to about 0.100", a wall thickness of from about 0.001" to about 0.004", and a length of from about A" to about 1 are produced at the rate of from about 30 to 60 per minute. With a similar machine of suitably increased dimensions, there maybe made, for example, beaded anodes having a diameter of up- What I claim is: 1. A machine for making tubular elements 1 from: thin-walled metal tubing comprising a rotatable member for holding a piece of tubing to effect rotation thereof, a scoring knife rotatable about an axis substantially parallel to the axis of rotation of said member, means for biasing said knife toward engagement with the tubing, means operable to permit said biasing means to move said knife toward and into contact with the tubing for rotation thereby during scoring and to limit the movement of said knife, and means for striking the tubing beyond the scoring to sever a section thereof.

2. Mechanism for feeding tubing comprising a chuck, two members through which the tubing passes to the chuck, a split sleeve about the tub ing, mechanism for reciprocating said members axially of said tubing, means for efiecting relative movement of said members to compress said sleeve upon the tubing while released from the chuck for one direction of their movement in unison and to release said sleeve from the tubing while held by the chuck for the opposite direction of their movement in unison, and means for effecting operation of said chuck to release and grip the tubing including a third reciprocable member extending alongside of said two members.

3. A machine for feeding tubing comprising a rotatable hollow member through which the tubing passes, a chuck at one end of said member for engaging the tubing to effect its rotation with said member, a pair of concentric sleeves about said tubing and within said member, mechanism operative intermittently to actuate the chuck to release the tubing including a third sleeve extending beyond the other end of said member a split sleeve compressed upon the tubing by relative movement in one direction of said pair of sleeves, mechanism operative in timed relation to said chuck-actuating mechanism for moving said pair of sleeves in unison in one direction while the tubing is held by said chuck and for moving them in reverse direction while the tubing is released from said chuck, and means for effecting relative movement of said pair of sleeves in one direction to compress said split sleeve'upon the tubing for movement with said concentric sleeves during their aforesaid reverse movement in unison and for effecting opposite relative movement of said pair of sleeves before their movement in unison in said one direction.

4. A machine comprising a rotatable member for gripping the work to effect rotation thereof, means for circumferentially scoring the work, reciprocating means for effecting engagement of said scoring means with the work at a distance beyond said member, structure carried by and rotatable with said member and movabl toward and away from the work, and mechanism operative during rotation of said member and in timed relation to said reciprocating means to effect movement of said structure to support the work adjacent the region of its engagement by said scoring means and so prevent flexure of the work during scoring thereof.

5. Mechanism for feeding tubing comprising three members through which the tubing passes and each of which is movable axially thereof, an element compressed by relative movement of two of said members in one direction to clamp said tubing and expanded upon relative movement of said two members in reverse direction to release the tubing, a chuck controlled by the third of said members, and cams individual to said members for effecting their reciprocation axially of said tubing to move said two members with respect to each other to compress and release said element and in unison with respect to said third member to eflect intermittent feed of the tubing through the chuck and to effect opening and closure of the chuck prior to compression and release respectively of said element.

6. A machine for making tubular elements comprising a rotatable member for externally gripping a piece of tubing to efiect rotation thereof, means for circumferentially scoring the tubing at a region thereof beyond said member, structure supported by and rotatable with said member and. movable toward and from the tubing adjacent said region, and means operable during rotation of said member to efiect movement of said structure toward and into engagement with the tubing to support it against flexure during its scoring.

7. A machine for making tubular elements comprising a rotatable member for externally gripping a piece of tubing to effect rotation thereof, means for circumferentially scoring the tubing beyond said member, means for striking the tubing beyond the scoring to sever a section thereof, structure rotatable with said member and movable toward and from the tubing, and means operable during rotation of said member to eifect movement of said structure toward and into engagement with the tubing to support it against fiexure during operations of said scoring an striking means. a

8. A machine for feeding thin-wall tubing comprising a hollow rotatable driving member, a collet having a hollow shank within and movable in opposite directions axially of said member, mechanism operable during rotation of said member intermittently to move said collet in opposite directions alternately to clamp upon and release tubing extending through said collet and beyond said member, two sleeves within and movable in opposite directions axially of said hollow shank, an element free of attachment to said sleeves compressed by their relative movement in one direction to clamp said tubing and expanded upon their relative movement in opposite direction to release the tubing, and mechanism operating in timed relation to said collet operating mechanism to effect aforesaid relative movements of said sleeves, to eflect their forward movement in unison with said element clamped upon the tubing and while said collet is released therefrom, and to effect their reverse movement with said element released from the tubing and while said collet is clamped thereon.

ANTON A. PRUCKNER.

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